function score = calculate_metabolites_occurence_weight1(metaboliteKEGGID, model)
    index = find(ismember(model.metKEGGID, metaboliteKEGGID),1);
    value = nnz(model.S(index,:));
    bound_3 = 2; %rare occurring compounds with
    bound_2 = 10; %medium frequency
    bound_1 = 20; %frequent occurring compounds
    score = 0;
    if value > bound_1
        score = 1;
    elseif bound_2 <= value && value <= bound_1
        score = 1 + (value-bound_1) * (bound_3-1) / (bound_2-bound_1);
    elseif bound_3 <= value && value < bound_2
        score = bound_3 + (value-bound_2) * (bound_2-bound_3) / (bound_3-bound_2);
    elseif 1 <= value && value < bound_3
        score = bound_2 + (value-bound_3) * (bound_1-bound_2) / (1-bound_3);
    end
end

    
    
    
    
    
    
    
    
    